Process of making sulfuric acid.



PATENTED SEPT. 1,1903.

J. B. F. HERRBSHOFF.

PROCESS OF MAKING SULFURIG ACID APPLIGATION FILED MAY 7, 1903.

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UNITED STATES Patented September 1, 1903.

PATENT OFFICE.

JOHN B. FRANCIS HERRESHOFF, OF NEW YORK, N. Y. ASSIGNOR TO GEN- ERALCHEMICAL COMPANY, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

PROCESS OF MAKING SULFURIC ACID.

SPECIFICATION forming part of Letters Patent No. 737,625, datedSeptember 1, 1903. Application filed May 7,1903. Serial No. 156,022. (Noe i e T ctZZ whom it may concern.-

Be it known that I, J OHN B. FRANCIS HER- RESHOFF, a citizen of theUnited States, and a resident of the borough of Manhattan, city, county,and State of New York, have invented certain new and useful Improvementsin Processes of Making Sulfuric Acid, of which the following is aspecification. My invention relates to the manufacture [O of sulfuricacid by the absorption of sulfuric anhydrid through the medium of liquidsulfuric acid of a lower density than that to be finally produced.

The object of my invention is to provide a continuous process of greatefficiency, in which provision will be made automatically for supplyingthe proper amount of absorbing liquid acid.

A plant suitable for carrying out my invention is shown in theaccompanying drawing, which is a diagrammatic elevation with parts insection.

A indicates the absorbing-tower filled with coke or irregular pieces ofother material, as designated at B. At 0, I have indicated an inletlocated at the bottom of the absorptiontower and into which the sulfuricanhydrid mixture produced in any suitable manner is introduced ingaseous form. In the upper 0 part of the tower A, I locate a spraying ordistributing device D, through which the liquid acid is discharged inthe shape of nu merous jets to trickle down over the coke or othermaterial B and to absorb the anhydrid which 3 5 travels in the oppositedirection. The anhydrid is forced through the absorption-tower in theusual way.

E is a pipe for the exit of the unabsorbed gases, consisting, chiefly,of nitrogen and oxy- 4o gen; but it will be understood that the sulfuricanhydrid is absorbed practically in its entirety.

The liquid sulfuric acid which is to absorb the anhydrid is suppliedfrom a tank G,which is connected with the distributing device D bya pipeII. An inlet-valve I or equivalent device controls the speed with whichthe liquid acid passes into the absorption-tower. This inlet-valve, asshown, has astem which screws in to a stationary bracket J, so thatthevalve may be' adjusted manually.

The strong acid which results from the absorption of the anhydrid by theliquid acid trickling over the material B is discharged through a pipe Kinto a tank L. This tank is divided into two compartments by a'partitionF, which is of less height than the walls of the tank, so that the aciddischarged into one of said compartments by the pipe K will afterfilling said compartment overflow into the other compartment. This othercompartment is connected with a manifold or other suitable distributingdevice M, arranged to discharge the liquid acid into a cooling-tank N.To this liquid acid I add an amount of water or weak acid sufficient toreduce the strength of the acid in the tank N to the strength which theacid originally had in the tank G. Preferably water is added to thestrong acid in that compartment of the tank L into which the acid flowsover the partition F. I have shown a, pipe 0, through which water orweak acid may be supplied. An overflow-pipe I, preferably leading fromthe bottom of thetank,so as to take thecoolportion of the liquid acid,is employed to convey the acid from the tank N to another tank Q,which Iwill term the regulator-tank. In this tank is arranged a float R,whichis operatively connected with a valve S, controlling anoutletpipeT,leading from the tank L. The operative connection mayconsist of a wire U, passing over rollersVand connected with a lever W,which engages the valve-stem. A weight X keeps the wire U taut and has atendency to open the valve S when the float rises. When, however, thefloat sinks, it will pull up the weight X and close the valve S. It willtherefore be seen that the float will automatically maintain apredetermined level in the regulating-tank Q by opening or closing thevalve S, so that the portion of strong acid which goes to thecooling-tank N will be in proper ratio to that portion of the strongacid which is discharged through the outlet T. The acid which flowsthrough the outlet T constitutes the output or product of the plant andis received in suitable receptacles, being first passed into acooling-tank Y of any suitable construction.

Within the regulating-tank Q is located a pump Z, preferably of thecentrifugal type; but I might employ any style of pump the suction-portof which would be connected sists of a rheostat I), having electricalconnections c with the electric motor d, the shaft 6 of which directlydrives the pump Z. With this construction should the float q fall thespeed of the motor at and of the pump Z will be increased, so as torestore the level of the liquid in the supply-tank G to its normalheight. Similarly should the level of the liquid rise too high onaccount of the pump Z feeding too much acid the rheostat will beoperated to reduce the speed of the pump.

In practice I may employ acid of, say, ninety-seven per cent. in thesupply-tank G. This acid as it absorbs the anhydrid in the tower A wouldbecome heated to, say, 145 Fahrenheit and increase in strength to, say,ninety-eight per cent. The final product of the plant received at theoutlet T would therefore be ninety-eight per cent. acid. The amount ofwater added through the pipe 0 would be such as to again restore theoriginal strength of the acid-that is, ninety-seven per cent. A manually-operated valvefmight be provided for regulating from time to timethe proportion of water admitted. The acid in the tank N will be cooledto about 100 Fahrenheit and will be brought back to the supply-tank G bythe pump Z. The valve I is set manually at the beginning of theoperation, but the ordinary regulation of the acid-supply to theabsorption-tower is effected by the float q, acting in connection withthe pump Z, as described. It will therefore be understood that there ispractically the same body of acid circulating continuously from theabsorption-tower to the coolingtank N, the regulating-tank Q, and thesupply-tank G. As this body of acid absorbs anhydrid and accordinglyrequires an increased strength, a portion of such strong acid isseparated to-form the product of the plant, while the remainder of thestrong acid is again diluted, cooled, and returned to the supply-tank. Ihave found that this is a very economical procedure and that very littlepower is required to bring about the circulation of the absorbing-acid.

It will be observed that the strong acid produced in theabsorption-tower is divided into two portions, one of which is separatedor reserved as the final product of the process, while the otherportion, which is much larger, is diluted and returned to the first Inthe stage of the process to absorb a furtheramount of anhydrid.

What I claim as new, and desire to secure by Letters Patent, is-

1. The herein-described method of making sulfuric acid,which consists incausing liquid sulfuric acid and gaseous sulfuric anhydrid to travel inopposite directions in contact with each other, reserving a portion ofthe strong acid thus produced as the final product of the process,diluting and cooling the remainder of the strong acid, and returningsuch diluted and cooled acid to the first stage of the process to againabsorb the anhydrid.

2. The herein-described process of manufaeturin g sulfuric acid,whichconsists in causing liquid sulfuric acid and gaseous anhydrid to'travelin contact with each other, reserving a portion of the strong acid thusproduced as the final product of the process, diluting and cooling theremainder of such strong acid, and returning such diluted and cooledproduct to the first stage of the process to again absorb the anhydrid.

3. The herein-described process of making sulfuric acid,which consistsin causing liquid sulfuric acid and sulfuric anhydrid to travel incontact with each other, separating a portion of the strong acidproduced as the final product of the process, diluting and cooling theremainder of the strong acid, and transferring the diluted and cooledproduct to the first stage of the process, and utilizing the variationin the level of the diluted and cooled product for governing theproportion of the strong acid which is separated as final product.

4. The herein-described process of manufacturing sulfuric acid,whichconsists in cansing liquid sulfuric acid and gaseous sulfuric anhydridto travel in contact with each other, separating the strong acidproduced into two portions, one of which constitutes the final product,diluting and cooling the other portion of the strong acid and thencollecting the product, transferring the said collected product to thefirst stage of the process, and utiliz ing the variations in the levelof the collected product to control the relative amounts of the twoportions taken from the strong acid.

5. The herein-described process of making sulfuric acid, which consistsin causing liquid sulfuric acid and gaseous sulfuric anhydrid to travelin contact with each other, diluting and cooling a portion of the strongacid thus produced,transferrin g and collecting,in readiness for areturn to the first stage of the process, the diluted and cooled productthus obtained, and utilizing the variations in the level of thecollected product to govern the amount of cooled, diluted acid which istransferred to the collected body.

6. The herein-described process of making sulfuric acid,which consistsin causing liquid sulfuric acid and gaseous sulfuric anhydrid to travelin contact with each other, separating the resulting strong acid intotwo portions, one of which is the final product, diluting and coolingthe other portion of the strong acid, collecting the cooled product,utilizing the variations in the level of the collected, cooled product,for-governing the proportion of the two portions of the strong acid,transferring and again collecting the cooled, diluted acid, as asupply-body, in readiness to be returned to the first stage of theprocess, and utilizing the variations in the level of the acid about tobe returned to the first stage of the process, for governing thetransfer of cooled acid to such supply-body.

In testimony whereof I have signed my 15 name to this specification inthe presence of two subscribing Witnesses.

JOHN B. FRANCIS HERRESHOFF.

\Vitnesses:

JOHN LOTKA, EUGENE EBLE.

